MINECRAFT SERVER

I recommend creating a folder for it. For example, I always create in my home folder the directory "mc" and put inside of it the minecraft_server.jar file. This is because, when you execute the server it will create several files and folders.

Now go to the folder where the minecraft_server.jar file is and either in the terminal or Nautilus GUI execute the file. in the terminal it would be:

java -Xmx1024M -Xms1024M -jar minecraft_server.jar nogui

I recommend using the nogui parameter to avoid an additional window in the GUI. Afterwards just close the server by either pressing CTRL+C in the terminal where you opened the minecraft server or by typing /stop in the minecraft server terminal. The latter will automatically save any progress. I mention the fact that you need to close it since, the first time you run the minecraft server, it will create all needed files, including the minecraft server configuration file which is called server.properties. Open this file with gedit for example and Edit anything you need in it before running the server again. Information about what each server property does can be found HERE